1. Field of Invention
The present invention relates to a fluid pumping device, in particular to a dispensing spray pump for fluid preparation.
2. Description of Related Arts
A spray pumping device for fluid preparation has been widespread used in the fields of medical treatment, cosmetic, perfume, etc., for dispensing and squirting the fluid preparation to form a spray. The fluid dispensing pumps, disclosed as in patent number CN 200680044054.1, patent application number CN 200980126767.6 and patent application number 201110308177.4, mainly include a water core, a piston and a dispensing head, the water core includes a plunger and a pump body, the plunger is clogged at a dispensing hole of the dispensing head, and the pump body has a chamber and is provided with a secondary piston consisting of annular rings on the exterior surface; the piston is fixed to the bottle mouth of the reagent bottle with fluid preparation through a fixing ring, the piston can move forth and back in the chamber in a sealing manner, the secondary piston is slidably disposed in the dispensing chamber of the dispensing head; the chamber is communicated with the dispensing chamber, the piston is slid in the chamber to discharge the fluid preparation into the dispensing chamber, the hydraulic pressure of the dispensing chamber increases to push the secondary piston sliding in the dispensing chamber to coordinate the plunger for breaking away from the dispensing hole, thereby dispensing outward a dose of fluid preparation.
Although the fluid dispensing pump as described above may pump drugs well, the structure itself has certain design defects, such as:
First, the water core in the above fluid dispensing pump consists of a plunger and a pump body being integrally formed, thereby resulting in a water core with complex structure and longer size. The corresponding piston requires moving forth and back in the pump body, and then forms a hydraulic device by combining the pump body; therefore, the piston also requires a length being matched with the pump body. Since both the water core and the piston adopt injection molding process, the long size would increase the difficulty in injection molding and withdrawal in the case of the requirement of guaranteeing precision.
Second, in the above fluid dispensing pump, the piston needs to move forth and back in the pump body in a sealing manner, moreover, a starting air channel is required to reserve between the outer wall of the piston and the inner wall of the pump body while the piston achieves in sealed sliding, which undoubtedly further increases the required precision of the pump body and the piston during the machining process, and is not conducive to improve production efficiency.
Aiming at the above defects of the structure of the existing fluid dispensing pump in practice, it is necessary to make further improvement of the prior art. The present invention is an improvement approach with regard to the defects.